Date of Award

Spring 5-28-2025

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Environmental Sciences

First Advisor

Beth A. Kaplin

Abstract

Montane landscapes of the Horn of Africa harbor exceptional but incompletely documented biodiversity. Focusing on rodents and shrews—the dominant but least studied of Ethiopia’s high-elevation fauna—this dissertation integrates repeat faunal surveys, genomic taxonomy, and phylogenetically informed modelling to clarify how small mammals distribute, diversify, and morphologically adapt across steep elevational gradients.

A century‐scale resurvey of Simien Mountains National Park (1927-2015) revealed significant upward range shifts for multiple species and a persistent mid-elevation richness peak, implicating warming temperatures as a driver of community reassembly. Museomics using genome-skimming and craniodental morphometrics subsequently uncovered a deeply divergent miniature shrew lineage within the Crocidura bottegi species complex; formal description of this new species elevates the recognized endemic mammal diversity of Ethiopia and underscores the prevalence of cryptic speciation in Afromontane “sky islands.” Finally, phylogenetically informed mixed-effects models tested Bergmann’s and Allen’s rules across five eastern African mountains. Body-mass patterns conformed to Bergmann’s prediction only in a subset of rodent clades, whereas shrews exhibited an inverse trend; tail-length variation offered no uniform support for Allen’s rule. These context-dependent responses highlight the interplay of temperature, resource limitation, and lineage-specific constraints in shaping montane phenotypes.

Collectively, the results demonstrate that (i) high-altitude small-mammal communities are rapidly reorganizing, (ii) endemic diversity remains underestimated even in well-surveyed parks, and (iii) classic ecogeographic “rules” inadequately capture trait evolution in tropical mountains. By coupling historical collections, modern fieldwork, and genomic tools, the dissertation provides a holistic framework for predicting how Africa’s montane mammals will respond to continuing climate change.

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